Aviva, Thomas Cook Group, and Dixons Retail are rising.

LONDON -- It's another day, another five-and-a-half-year high for the FTSE 100(FTSEINDICES:^FTSE). The index of top U.K. shares is up 0.25% to 6,710 points as of 8:30 a.m. EDT, and it has now seen 10 consecutive days of gains and spent eight days above the 6,500 level.

Which companies are supporting the current bullish mood? Here are three whose shares are on the up today.

AvivaAviva shares have been boosted by first-quarter figures this morning, gaining 7.8%. The insurer said new business is up 18% to 191 million pounds due to improved profitability in its U.K. and Asian markets. Restructuring costs caused a 54 million pound hit, but that was more than offset by a 10% reduction in operating expenses to 769 million pounds, and the firm is still on track for cost savings of 400 million pounds.

The firm's net asset value has risen 9% to 302 pence per share, and its internal debt level is down by 300 million pounds. Chief executive Mark Wilson said, "Progress so far has been satisfactory and there is a great deal more we need to do for our shareholders."

Thomas CookIf you want to see the kind of recovery that blows your socks off, look no further than Thomas Cook Group. From the brink of the abyss a year ago, the company is back, and its share price has more than eight-bagged to today's 156 pence, helped by 13.6% boost today. The travel firm released half-year figures and announced a capital reorganization. The new financing includes a 425 million pounds placing and rights issue, a 441 million pound bond issue, and 691 million pounds in new facilities.

As for the results, EBIT in the loss-making half of the year has improved by 58.7 million pounds to a loss of 197.5 million pounds, with underlying gross margin up 110 points to 20.7%. Net debt dropped by 175 million pounds to 1.2 billion pounds, and bookings are said to be strong.

DixonsSpeaking of recoveries, the one at Dixons Retail has been pretty impressive, too, and the shares have climbed another 7.9% today -- they're now up 150% over the past 12 months. The driver today was a full-year trading update for the year to April 30.

Dixons' earlier failure was in not embracing online trading, but what is now known as its "multi-channel business" saw a rise a 7% in like-for-like sales over the whole year, with a fourth-quarter rise of 11%. The firm also achieved strong cash-generation, leading to a year-end net cash position for the first time in years.

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